5 ms·

Yeah, you have to remember that in pulse dial days a central office station had a reach of roughly 3 miles. The longer you go, the more you're paying for cable,

Yeah, you have to remember that in pulse dial days a central office station had a reach of roughly 3 miles. The longer you go, the more you're paying for cable, repeaters, or just losing quality. 90 volt AC for ringing has a limited range!

walrus01 8y ago
People who've never seen it in person find it amazing that things like 1200 pair phone cables exist... Here's a photo of just a 100-pair: https://imgur.com/gallery/f1EGp https://imgur.com/gallery/f1EGp on this page is a photo of a 1200-pair: http://cityinfrastructure.com/single.php?d=RuralOutsidePlant&t=Rural%20Outside%20Plant http://cityinfrastructure.com/single.php?d=RuralOutsidePlant...
- foobar1962 8y ago
  How do they colour-code the wires to identify them? "Ah there's your problem: you've patched the Fire Engine Red pair, it's meant to be the Ferrari Red. Rookie error."
  - tmm 8y ago
    > How do they colour-code the wires to identify them? It’s actually pretty simple. There are only 10 colors: blue, orange, green, brown, slate, white, red, black, yellow, and violet. They’re grouped in “binders” (using colored strings). You’re likely familiar with the first four pairs from network cables (which omit the white/slate pair). After cylcling through blue through slate paired with white through violet (25 pairs), the wires are bundled with binders starting with blue/white string. That gets you to 625 pairs (the first picture posted above is 600 or 625 pairs). After that, the binder groups are bound in a similar fashion (typically if you’re going beyond 625, the slate/violet binder is omitted to get a nice round 600 in the first group). Wikipedia has a good article: https://en.m.wikipedia.org/wiki/25-pair_color_code https://en.m.wikipedia.org/wiki/25-pair_color_code 100-pair cable is only about 3/4” diameter. I have a 24-line 1A2 telephone that uses 75 pairs just to connect to the phone switch and two 100-pair cables feeding a telephone display case in my living room. It takes me about a half hour to punch down 100 pairs on a 66-block. Old school telecom guys could probably do it in under 10 minutes.
    - scoggs 8y ago
      What about if you are color blind? Change professions?
      - walrus01 8y ago
        Yes. Same problem for fiber fusion splicers. Worked for an ISP that hired a color blind person as a field tech, he didn't last long.
- freeflight 8y ago
  I'm pretty sure we have Human Rights Conventions to protect people from having to crimp a mess like that. At least I hope so, if not, then they really should exist.

walrus01 8y ago

People who've never seen it in person find it amazing that things like 1200 pair phone cables exist... Here's a photo of just a 100-pair: https://imgur.com/gallery/f1EGp https://imgur.com/gallery/f1EGp on this page is a photo of a 1200-pair: http://cityinfrastructure.com/single.php?d=RuralOutsidePlant&t=Rural%20Outside%20Plant http://cityinfrastructure.com/single.php?d=RuralOutsidePlant...

foobar1962 8y ago
How do they colour-code the wires to identify them? "Ah there's your problem: you've patched the Fire Engine Red pair, it's meant to be the Ferrari Red. Rookie error."
- tmm 8y ago
  > How do they colour-code the wires to identify them? It’s actually pretty simple. There are only 10 colors: blue, orange, green, brown, slate, white, red, black, yellow, and violet. They’re grouped in “binders” (using colored strings). You’re likely familiar with the first four pairs from network cables (which omit the white/slate pair). After cylcling through blue through slate paired with white through violet (25 pairs), the wires are bundled with binders starting with blue/white string. That gets you to 625 pairs (the first picture posted above is 600 or 625 pairs). After that, the binder groups are bound in a similar fashion (typically if you’re going beyond 625, the slate/violet binder is omitted to get a nice round 600 in the first group). Wikipedia has a good article: https://en.m.wikipedia.org/wiki/25-pair_color_code https://en.m.wikipedia.org/wiki/25-pair_color_code 100-pair cable is only about 3/4” diameter. I have a 24-line 1A2 telephone that uses 75 pairs just to connect to the phone switch and two 100-pair cables feeding a telephone display case in my living room. It takes me about a half hour to punch down 100 pairs on a 66-block. Old school telecom guys could probably do it in under 10 minutes.
  - scoggs 8y ago
    What about if you are color blind? Change professions?
    - walrus01 8y ago
      Yes. Same problem for fiber fusion splicers. Worked for an ISP that hired a color blind person as a field tech, he didn't last long.
freeflight 8y ago
I'm pretty sure we have Human Rights Conventions to protect people from having to crimp a mess like that. At least I hope so, if not, then they really should exist.